Table of Contents
Many believe that theory that cholesterol causes cardiovascular disease is just a myth, so there is no need to monitor cholesterol numbers. The truth is, however, that cholesterol actually is critical to the process of atherogenesis that clogs arteries. The cholesterol that causes the clogs, however, is not the cholesterol that is usually measured.
What Is Cholesterol?
Cholesterol is usually described as a fatty, waxy substance, but the kind of cholesterol in our bloodstreams is actually something quite different.
Fats do not dissolve in water. Cholesterol could not be transported through the bloodstream except for being coated with proteins that are water-soluble. Without a balloon-like layer of lipoprotein, cholesterol could never enter circulation.
The body makes about 85% of the cholesterol in circulation, the other 15% coming from food. The basic building blocks of cholesterol are triglycerides, which store unused carb calories as a substance called glycerol, combining them with unused fatty acids. Triglycerides can be broken down into fuel, or the liver can process them into smaller, protein-coated particles of cholesterol. Not all kinds of cholesterol function in the same way in the human body.
What Are the Different Kinds of Cholesterol?
When we get our cholesterol numbers, we are usually told our total cholesterol. Total cholesterol is (1) a fatty substance that has to be coated with protein to circulate through the bloodstream but is not (2) a triglycerides. The lab measures total lipids and triglycerides, and what's left is cholesterol.
The "balloon" of protein coating cholesterol, however, may be of various sizes. The lightest, fluffiest, largest particles of cholesterol are known as very low-density lipoprotein or VLDL cholesterol. As VLDL cholesterol circulates through the body and its glycerol and fatty acids are used to fuel muscles and internal organs, it shrinks into a slightly denser form known as low-density lipoprotein or LDL cholesterol.
The liver can extract still more fatty acids and glycerol from LDL cholesterol to make high-density lipoprotein or HDL cholesterol. But why does the size of cholesterol make a difference?
Some particles of cholesterol are too large to get trapped in the linings of arteries. Some are too small. LDL cholesterol is the "bad" cholesterol that can contribute to the process of calcification, but not even every kind of LDL cholesterol is harmful. Only the just-large-enough pieces of cholesterol known as apoliprotein B1 (or apo-B1) is capable of "unlocking" white blood cells in the linings of arteries so that they fill up with cholesterol and eventually calcify into the plaques that block arteries.
Neither triglycerides nor any of the various forms of cholesterol is always good or bad. The process of plaque formation depends on more than just the presence of cholesterol, even the kind of cholesterol that can get trapped in the lining of an artery.